Top US intelligence officials have said Russia’s “highly-advanced offensive cyber program” is a major threat to America’s government and infrastructure.

Some of the highest ranking intelligence officials in the US are giving testimony to US Senate Armed Services Committee investigating claims of Russian interference in the US election this afternoon.

The claims were made by director of national intelligence James Clapper, undersecretary of defence for intelligence Marcel Lettre, and Admiral Michael Rogers, director of the National Security Agency (NSA).

"Russia is a full-scope cyber actor that poses a major threat to US government, military, diplomatic, commercial and critical infrastructure," the three officials said in a joint testimony.

The committee is investigating whether Russian hacking had any influence on this year's US presidential election.

Moscow has been accused of helping to sway the US presidential election result by hacking into emails of the Democratic National Committee.

The three spy chiefs believe Moscow's top leadership was behind the hacking in an effort to help Republican Donald Trump defeat Democrat Hillary Clinton.

In a joint statement, they said: "We assess that only Russia's senior-most officials could have authorised the recent election-focused data thefts and disclosures."

A report on election meddling by Russia and other foreign countries has been delivered to President Barack Obama.

Armed Services Committee chairman, Senator John McCain said the probe is not intended to question the result of the election.

The President-elect Donald Trump has expressed scepticism that Russia was behind the election hacking.